The present invention relates to rendering devices and, more specifically, to a rendering device which can be incorporated in a drive assistant device. In more detail, the rendering device generates a display image of an area around a vehicle based on an image that is captured by an image capture device fixedly placed in the vehicle.
The drive assistant device incorporating such a rendering device as described above has been actively researched and developed. A conventional-type drive assistant device is mounted in a vehicle, and generally includes an image capture device, a rudder angle sensor, a computing unit, a rendering device, and a display device. The image capture device is fixedly placed in a predetermined position in the vehicle, and the image capture device is provided for capturing an image of an area that is defined by the viewing angle of the image capture device. The resulting image is hereinafter referred to as a captured image. The rudder angle sensor is also fixed in a predetermined position in the vehicle, and detects to what degree the steering wheel of the vehicle is turned. Based on the detection result, the computing unit calculates an estimated path for the vehicle to take. The rendering device then renders the estimated path on the captured image, and the image generated thereby is a display image such as the one shown in FIG. 20. The display image is displayed on the display device.
With such a display image on the display device, a driver of the vehicle can know if his/her current steering will fit the vehicle in a parking space without colliding into any obstacle in a close range of the driver""s vehicle. If his/her steering is not appropriate, the estimated path is displayed out of the parking space in the display image. Therefore, the driver can appropriately adjust the rudder angle of the steering wheel.
There is another type of conventional drive assistant device exemplarily disclosed in Japanese Patent examined Publication No. 2-36417 (1990-36417). The drive assistant device additionally carries an active sensor for measuring a distance between the vehicle and an obstacle that is observed near the estimated path. Based on the measurement result provided by the active sensor, the computing unit determines which part of the estimated path is to be rendered on the captured image. The part which is determined to be rendered on the captured image is hereinafter referred to as a rendering estimated path. In this manner, the rendering device accordingly renders on the captured image the rendering estimated path, which ends right before the obstacle.
The above-described conventional drive assistant devices have the following two problems. First, the estimated path is fixedly determined in color for display. Thus, even if the color is similar in tone to a predominant color of the display image, the color is unchangeable. Here, the predominant color is mainly determined by the road, for example, regardless of whether the road paved or not with asphalt. If this is the case, the driver finds it difficult to instantaneously locate the estimated path on the display image.
Second, the estimated path that is rendered in the display image is represented simply by lines, which fails to help the driver instantaneously perceive how far he/she can move the vehicle. More specifically, as shown in FIG. 21, a vehicle Vusr carrying the conventional drive assistant device is moving toward an obstacle Vbst. In this case, the vehicle Vusr first collides into a corner point Pcnr of the obstacle Vbst, not intersection points Pcrg of an estimated path Pp and the surface of the obstacle Vbst. This means that the farthest point possible for the vehicle Vusr to move is the corner point Pcnr of the obstacle Vbst. As such, even if the estimated path is so rendered as to end immediately before the object, the second problem remains yet unsolved.
Therefore, an object of the present invention is to provide a rendering device which generates display image that shows an estimated path in an eye-catching manner for the driver to easily locate.
Another object of the present invention is to provide a rendering device which generates display image generated that is indicative and helpful for the driver to know how far he/she can move the vehicle.
The present invention has the following features to attain the above-described objects.
A first aspect of the present invention is directed to a rendering device for generating a display image of an area around a vehicle for drive assistance. The rendering device comprises a reception part for receiving a current rudder angle of a steering wheel of the vehicle from a rudder angle sensor fixed in the vehicle; a derivation part for deriving an estimated path for the vehicle to take based on the rudder angle received by the reception part; and an image generation part for generating the display image based on a captured image which is captured by an image capture device fixed in the vehicle, and the estimated path that is derived by the derivation part. Here, in the display image, the estimated path is overlaid on an intermittent basis.
A second aspect of the present invention is directed to a rendering device for generating a display image of an area around a vehicle for drive assistance. The rendering device comprises a first reception part for receiving a distance to an obstacle that is located around the vehicle from a measuring sensor placed in the vehicle; a first derivation part for deriving a farthest point for the vehicle to move based on the distance received by the first reception part; a second reception part for receiving a current rudder angle of a steering wheel of the vehicle from a rudder angle sensor fixed in the vehicle; a second derivation part for deriving an estimated path for the vehicle to take based on the rudder angle received by the second reception part; and an image generation part for generating the display image based on a captured image which is captured by an image capture device fixed in the vehicle, the farthest point derived by the first derivation part, and the estimated path derived by the second derivation part.
These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.